Sex chromosomes are the chromosomes within a cell that carry the genes important in the determination of the sex of an organism. In the cells of all diploid organisms, with the exception of the sperm and eggs and the gametophyte generation in plants, chromosomes are arranged in pairs called homologous pairs. Each chromosome in the homologous pair comes from a different parent. A cell that has both chromosomes of each homologous pair is a diploid cell. In the human body, diploid cells have 46 chromosomes arranged in 23 homologous pairs.

In humans, each diploid cell has two sex chromosomes that make up one of the 23 homologous pairs of chromosomes. There are two types of sex chromosomes, the X chromosome and the Y chromosome. The X chromosome is larger than the Y chromosome, and, therefore, has spaces for genes that are not present on the Y chromosome.

In humans...